Molded waterway for a two handle faucet

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a national phase filing of PCT International Application Serial No. PCT/US2009/040207, filed Apr. 10, 2009, which claims the benefit of U.S. Provisional Patent Application Ser. No. 61/123,714, filed Apr. 10, 2008, the disclosures of which are expressly incorporated herein by reference.

BACKGROUND AND SUMMARY OF THE INVENTION

The present invention relates generally to plumbing fixtures and, more particularly, to a faucet including a molded waterway assembly.

Faucets are generally controlled by either a single handle which utilizes a mixing valve to proportion the flow of hot water and cold water to a delivery spout, or dual handles which utilize two separate valves to independently control the flow of hot water and cold water. In a conventional dual handle faucet, the hot water and cold water valve bodies, which house the respective hot water and cold water valves, are each typically connected to an upstream waterway through a conventional mechanical connection, such as mating threads. Further, each valve body is typically connected to a separate downstream waterway. In certain examples, the valve bodies and the downstream waterways are sand cast from brass, or are machined from brass components and combined through brazing. Sand casting is typically a manual low-tech process that if not controlled properly may lead to failures through pin holes or porosity. One of the potential problems with a brazing connection is that undesirable materials, such as harmful metals, may be communicated from the brazing material into the water passageway through the brazed connection. Further, brazing is often a variable process that may lead to failures. Additionally, brazing often requires an etching operation to be performed subsequent thereto.

According to an illustrative embodiment of the present disclosure, a waterway assembly for use with a centerset faucet includes a first flexible tube including opposing proximal and distal ends, and a second flexible tube including opposing proximal and distal ends. The proximal end of the second flexible tube is positioned in spaced relation to the proximal end of the first flexible tube. A coupler includes a first valve support having a first valve interface and overmolded about the proximal end of the first flexible tube, and a second valve support having a second valve interface and overmolded about the proximal end of the second flexible tube. An outlet tube interface is positioned intermediate the first valve support and the second valve support. The outlet tube interface is configured to be in fluid communication with an outlet tube. A first fluid connector is fluidly coupled intermediate the first valve support and the outlet tube interface, and a second fluid connector is fluidly coupled intermediate the second valve support and the outlet tube interface.

According to a further illustrative embodiment of the present disclosure, a waterway assembly for use with a centerset faucet includes a hot water inlet tube having opposing proximal and distal ends, and a cold water inlet tube including opposing proximal and distal ends. A coupler includes an outlet positioned intermediate the proximal end of the hot water inlet tube and the proximal end of the cold water inlet tube. The coupler is an overmold of the proximal end of the hot water inlet tube and the proximal end of the cold water inlet tube. The overmold includes a hot water fluid connector including an internal waterway fluidly coupling the hot water inlet tube to the outlet, and a cold water fluid connector including an internal waterway fluidly coupling the cold water inlet tube to the outlet.

According to another illustrative embodiment of the present disclosure, a faucet for connection to a hot water supply and a cold water supply is provided. The faucet includes a hot water inlet tube having opposing proximal and distal ends, the distal end configured to be fluidly coupled to the hot water supply. The faucet further includes a cold water inlet tube having opposing proximal and distal ends, the distal end configured to be fluidly coupled to the cold water supply A coupler includes a hot water valve support including a hot water valve interface and overmolded about the proximal end of the hot water inlet tube, and a cold water valve support including a cold water valve interface and overmolded about the proximal end of the cold water inlet tube. An outlet tube interface is positioned intermediate the hot water valve support and the cold water valve support. A hot water fluid connector includes an internal waterway fluidly coupling the hot water inlet tube to the outlet tube interface, and a cold water fluid connector includes an internal waterway fluidly coupling the cold water inlet tube to the outlet tube interface. The hot water valve support, the cold water valve support, the outlet tube interface, the hot water fluid connector, and the cold water fluid connector are integrally molded from a polymer. A hot water valve is operably coupled to the hot water valve support to control the flow rate of hot water through the internal waterway of the hot water fluid connector, and a cold water valve is operably coupled to the cold water valve support to control the flow rate of cold water through the internal waterway of the cold water fluid connector.

According to another illustrative embodiment of the present disclosure, a method of forming a waterway for a faucet includes the steps of providing a mold including a cavity, providing a first tube including opposing proximal and distal ends, providing a second tube including opposing proximal and distal ends, placing the proximal end of the first tube within the cavity of the mold, inserting a first mandrel into the proximal end of the first tube, placing the proximal end of the second tube within the cavity of the mold in spaced relation to the proximal end of the first tube, and inserting a second mandrel into the proximal end of the second tube. The method further includes the steps of positioning a pin within the cavity of the mold intermediate the first mandrel and the second mandrel, injecting a flowable material within the cavity of the mold, withdrawing the first mandrel and the second mandrel to form first and second valve interfaces, and withdrawing the pin to form an outlet interface.

Additional features and advantages of the present invention will become apparent to those skilled in the art upon consideration of the following detailed description of the illustrative embodiment exemplifying the best mode of carrying out the invention as presently perceived.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description of the drawings particularly refers to the accompanying figures in which:

<figref idref="DRAWINGS">FIG. 1</figref> is a perspective view of an illustrative faucet of the present disclosure mounted to a sink deck and fluidly coupled to hot and cold water supply lines;

<figref idref="DRAWINGS">FIG. 2</figref> is a top plan view of an illustrative molded waterway for use with the faucet of <figref idref="DRAWINGS">FIG. 1</figref>;

<figref idref="DRAWINGS">FIG. 2A</figref> is a detailed top plan view of a further illustrative valve support for the molded waterway of <figref idref="DRAWINGS">FIG. 2</figref>;

<figref idref="DRAWINGS">FIG. 3</figref> is a bottom plan view of the molded waterway of <figref idref="DRAWINGS">FIG. 2</figref>;

<figref idref="DRAWINGS">FIG. 4</figref> is a cross-sectional view taken along line <b>4</b>-<b>4</b> of <figref idref="DRAWINGS">FIG. 2</figref>;

<figref idref="DRAWINGS">FIG. 5</figref> is a perspective view of the molded waterway of <figref idref="DRAWINGS">FIG. 2</figref>;

<figref idref="DRAWINGS">FIG. 6</figref> is a flow chart of an illustrative method of forming the molded waterway of <figref idref="DRAWINGS">FIG. 2</figref>;

<figref idref="DRAWINGS">FIG. 7</figref> is a perspective view of an illustrative bottom mold portion for use in forming the waterway of <figref idref="DRAWINGS">FIG. 2</figref>;

<figref idref="DRAWINGS">FIG. 8</figref> is a perspective view of an illustrative upper mold portion for forming the waterway of <figref idref="DRAWINGS">FIG. 2</figref>; and

<figref idref="DRAWINGS">FIG. 9</figref> is a cross-sectional view of an illustrative molded waterway prior to trimming overflow portions and including a fluid directing feature.

DETAILED DESCRIPTION OF THE DRAWINGS

The embodiments of the invention described herein are not intended to be exhaustive or to limit the invention to precise forms disclosed. Rather, the embodiments selected for description have been chosen to enable one skilled in the art to practice the invention.

Referring initially to <figref idref="DRAWINGS">FIG. 1</figref>, an illustrative embodiment faucet <b>10</b> is shown mounted to a sink deck <b>12</b>. The faucet <b>10</b> is fluidly coupled to hot and cold water supplies <b>16</b> and <b>18</b> through conventional stops (not shown). Hot and cold water fluid transport components, or inlet tubes <b>20</b> and <b>22</b> include opposing proximal and distal ends <b>20</b><i>a</i>, <b>22</b><i>a</i>, and <b>20</b><i>b</i>, <b>22</b><i>b</i>, respectively. Illustratively, the tubes <b>20</b> and <b>22</b> are flexible such that the distal ends <b>20</b><i>b</i>, <b>22</b><i>b </i>may be manipulated relative to the respective proximal ends <b>20</b><i>a</i>, <b>22</b><i>a</i>. Fluid couplings <b>24</b> and <b>26</b> are provided at distal ends <b>20</b><i>b </i>and <b>22</b><i>b </i>for connecting with the hot and cold water supplies <b>16</b> and <b>18</b>, respectively. It should be appreciated that the inlet tubes <b>20</b> and <b>22</b> may be directly coupled to the respective hot and cold water stops through couplings <b>24</b> and <b>26</b> or, alternatively, to intermediate hot and cold water risers (not shown).

Illustratively, the tubes <b>20</b> and <b>22</b> are formed of a polymer, such as an olefin or a polyethylene. In one illustrative embodiment, the tubes <b>20</b> and <b>22</b> are formed of a polyethylene which has been cross-linked to form cross-linked polyethylene (PEX). However, it should be appreciated that other suitable materials may be substituted therefor.

A hot water valve <b>30</b> is fluidly coupled to the hot water inlet tube <b>20</b>, while a cold water valve <b>32</b> is fluidly coupled to the cold water inlet tube <b>22</b>. A coupler or molded waterway <b>34</b> includes a first or hot water internal waterway <b>36</b> fluidly coupling the hot water valve <b>30</b> to an outlet tube <b>38</b>. The coupler <b>34</b> further includes a second or cold water internal waterway <b>40</b> fluidly coupling the cold water valve <b>32</b> to the outlet tube <b>38</b>.

The hot water valve <b>30</b> includes a valve member <b>31</b> that is movable between a first position where water from the hot water inlet tube <b>20</b> is in fluid communication with the internal waterway <b>36</b>, and a second position where water from the hot water inlet tube <b>20</b> is not in fluid communication with the internal waterway <b>36</b>. Arrows <b>39</b> in <figref idref="DRAWINGS">FIG. 4</figref> represent hot water flow through valve <b>30</b> from inlet tube <b>20</b> to waterway <b>36</b>, and subsequently to outlet tube <b>38</b>. In one illustrative embodiment, the valve member <b>31</b> of hot water valve <b>30</b> is a rotatable disc wherein the rotational position of the disc <b>31</b> is adjusted through a hot water user input, such as a handle <b>42</b>. Handle <b>42</b> generally extends above an escutcheon <b>44</b> of the faucet <b>10</b> and is rotatable in the direction of arrow <b>45</b> in <figref idref="DRAWINGS">FIG. 1</figref>. It should be appreciated that the handle <b>42</b> may be replaced with other user inputs, such as a lever.

Similarly, cold water valve <b>32</b> includes a valve member <b>33</b> that is movable between a first position where water from the cold water inlet tube <b>22</b> is in fluid communication with internal waterway <b>40</b>, and a second position where water from the cold water inlet tube <b>22</b> is not in fluid communication with internal waterway <b>40</b>. Arrows <b>45</b> in <figref idref="DRAWINGS">FIG. 4</figref> represent cold water flow through valve <b>32</b> from inlet tube <b>22</b> to waterway <b>40</b>, and subsequently to outlet tube <b>38</b>. In one illustrative embodiment, the valve member <b>33</b> of cold water valve <b>32</b> is a rotatable disc that may be rotatably adjusted through a cold water user input, such as a handle <b>46</b>. Handle <b>46</b> generally extends above escutcheon <b>44</b> of the faucet <b>10</b> and is rotatable in the direction of arrow <b>47</b> in <figref idref="DRAWINGS">FIG. 1</figref>. As with handle <b>42</b>, handle <b>46</b> may be replaced with other user inputs, such as a lever. A delivery spout <b>48</b> is supported above the escutcheon <b>44</b> and receives the outlet tube <b>38</b>. While the drawings illustrate the coupler <b>34</b> supporting the base of the delivery spout <b>48</b> rearward of the valves <b>30</b> and <b>32</b>, in other illustrative embodiments the coupler <b>34</b> may be oriented <b>180</b> degrees from that shown in <figref idref="DRAWINGS">FIGS. 1 and 2</figref> such that the base of the delivery spout <b>48</b> is positioned forward of the valves <b>30</b> and <b>32</b>. Such an orientation may provide additional space for a conventional drain lift rod (not shown) of faucet <b>10</b>.

In one illustrative embodiment, the valves <b>30</b> and <b>32</b> may be of the type disclosed in U.S. Patent Application Ser. No. 61/132,664, filed Jun. 20, 2008, the disclosure of which is expressly incorporated by reference herein. Additional exemplary rotatable valves are disclosed in U.S. Pat. Nos. 3,645,493; 4,453,567; 4,577,835; and 4,700,928.

With reference now to <figref idref="DRAWINGS">FIGS. 2-5</figref>, the coupler <b>34</b> includes a first valve support <b>50</b> having a first valve interface <b>52</b> and overmolded about the proximal end <b>20</b><i>a </i>of the hot water inlet tube <b>20</b>. The coupler <b>34</b> further includes a second valve support <b>54</b> having a second valve interface <b>56</b> and overmolded about the proximal end <b>22</b><i>a </i>of the cold water inlet tube <b>22</b>. An outlet tube interface <b>58</b> is positioned intermediate the first valve support <b>50</b> and the second valve support <b>54</b> and is configured to be in fluid communication with the outlet tube <b>38</b>. A first or hot water fluid connector <b>60</b> defines the internal waterway <b>36</b> fluidly coupling the first valve support <b>50</b> and the outlet tube interface <b>58</b>. A second or cold water fluid connector <b>62</b> defines the second internal waterway <b>40</b> and fluidly couples the second valve support <b>54</b> and the outlet tube interface <b>58</b>. While the outlet tube interface <b>58</b> is shown in <figref idref="DRAWINGS">FIG. 2</figref> positioned rearward of the valve supports <b>50</b> and <b>54</b>, in other illustrative embodiments the outlet tube interface <b>58</b> may be substantially aligned with, or positioned forward of, the valve supports <b>50</b> and <b>54</b>.

As further detailed herein, the coupler <b>34</b> is formed of a flowable material which is overmolded around the proximal ends <b>20</b><i>a </i>and <b>22</b><i>a </i>of the inlet tubes <b>20</b> and <b>22</b> while defining the internal waterways <b>36</b> and <b>40</b> for hot and cold water from the valves <b>30</b> and <b>32</b>, respectively. While any suitable material may be used to form coupler <b>34</b>, a polymer, including thermoplastics and thermosets, is utilized in the illustrative embodiment. More particularly, the coupler <b>34</b> is illustratively molded as a single integral component including first and second valve supports <b>50</b> and <b>54</b>, fluid connectors <b>60</b> and <b>62</b> defining internal waterways <b>36</b> and <b>40</b>, and outlet tube interface <b>58</b>. In the illustrative embodiment detailed herein, the coupler <b>34</b> is formed of polyethylene which has been overmolded around the inlet tubes <b>20</b> and <b>22</b> and subsequently cross-linked. It should be noted that reinforcing members, such as glass fibers, may be provided within the polyethylene of the coupler <b>34</b>.

The basic principles of overmolding plumbing connections on tubes are shown in U.S. Pat. Nos. 5,895,695; 6,082,780; 6,287,501; and 6,902,210. U.S. Patent Application Publication Nos. 2007/0271695 and 2007/0044852 also disclose illustrative overmolding about water inlet tubes.

With reference to <figref idref="DRAWINGS">FIGS. 2</figref>, <b>4</b>, and <b>5</b>, valve interfaces <b>52</b> and <b>56</b> of the first and second valve supports <b>50</b> and <b>54</b> each include an upwardly projecting inlet wall <b>64</b> extending around an inlet port <b>65</b>, and an upwardly projecting outlet wall <b>66</b> extending around an outlet port <b>67</b>. The inlet and outlet walls <b>64</b> and <b>66</b> define a trench <b>68</b> for receiving a resilient gasket <b>70</b> (<figref idref="DRAWINGS">FIGS. 4 and 5</figref>). The gasket <b>70</b> may be formed of an elastomer and provides a seal intermediate the respective valves <b>30</b>, <b>32</b> and valve support <b>50</b>, <b>54</b>. While the inlet tubes <b>20</b> and <b>22</b> as shown in <figref idref="DRAWINGS">FIG. 2</figref> define a circular cross-section, it should be noted that the cross-sectional shape of the inlet tubes <b>20</b> and <b>22</b> within the valve supports <b>50</b> and <b>54</b> may vary. For example, the cross-section of the proximal ends <b>20</b><i>a </i>and <b>22</b><i>a </i>of inlet tubes <b>20</b> and <b>22</b> may be oval or D-shaped in order to facilitate material flow during the molding operation for defining an increased and/or substantially consistent thickness of inlet wall <b>44</b>. With reference to <figref idref="DRAWINGS">FIG. 2A</figref>, inlet port <b>65</b>′ is defined by the proximal end <b>22</b><i>a </i>of inlet tube <b>22</b> as substantially oval shaped thereby providing a substantially continuous and uniform inlet wall <b>64</b>′ for valve interface <b>56</b>′. The increased thickness of portions of inlet wall <b>64</b>′ may provide additional support for the valves <b>30</b> and <b>32</b> and sealing between the valve interfaces <b>52</b>′ and <b>56</b>′ and the valves <b>30</b> and <b>32</b>.

A plurality of locating notches <b>71</b> are illustratively formed around a periphery of the valve supports <b>50</b> and <b>54</b> and are configured to receive locating tabs of the valves <b>30</b> and <b>32</b>, respectively, to facilitate orientation therebetween. The outlet tube interface <b>58</b> includes a counterbore <b>72</b> for receiving an o-ring <b>74</b> to provide a seal intermediate a female coupler ring or collar <b>75</b> of the outlet tube <b>38</b> and the interface <b>58</b>.

With reference now to <figref idref="DRAWINGS">FIGS. 6-8</figref>, an illustrative method of forming the waterway assembly of the present disclosure includes the use of a mold including a lower mold portion <b>76</b> (<figref idref="DRAWINGS">FIG. 7</figref>), and an upper mold portion <b>78</b> (<figref idref="DRAWINGS">FIG. 8</figref>) defining a cavity <b>80</b> therebetween. As shown at step <b>100</b> in <figref idref="DRAWINGS">FIG. 6</figref>, the proximal end <b>20</b><i>a </i>of the hot water inlet tube <b>20</b> is passed through an opening <b>82</b> in the upper mold portion <b>78</b> and a first mandrel <b>84</b> of the lower mold portion <b>76</b> is positioned therewithin. Similarly, the proximal end <b>22</b><i>a </i>of the cold water inlet tube <b>22</b> extends through an opening <b>88</b> in the upper mold portion <b>78</b> and has a second mandrel <b>90</b> of the lower mold portion positioned therein. The mandrels <b>84</b> and <b>90</b> properly locate the tubes <b>20</b> and <b>22</b> and prevent the tubes <b>20</b> and <b>22</b> from moving during the molding process. The mandrels <b>84</b> and <b>90</b> also prevent the walls of the tubes <b>20</b> and <b>22</b> from collapsing during the molding process. A pin <b>92</b> is supported within the cavity <b>80</b> of the mold intermediate the first mandrel <b>84</b> and the second mandrel <b>90</b> and is configured to define the outlet tube interface <b>58</b>.

At step <b>102</b>, a flowable material, illustratively a polymer such as polyethylene, is injected into the cavity <b>80</b> of the mold. The pin <b>92</b> illustratively includes a fluid conduit extending therethrough for providing a fluid connection for a gas assist molding process. More particularly, once the flowable material has started to cool or solidify at step <b>104</b>, a fluid, illustratively a gas such as compressed air, is injected through the pin <b>92</b> defining the outlet tube interface <b>58</b> (step <b>108</b>). Simultaneously or immediately beforehand, a valve (not shown) is opened allowing displaced polymer to exit the final part configuration into overflow chambers <b>94</b> and <b>96</b> (step <b>106</b>). The compressed air displaces plastic from the still molten center of the part into overflow chambers <b>94</b> and <b>96</b>. In one illustrative embodiment, fluid directing features <b>93</b><i>a</i>, <b>93</b><i>b</i>, and <b>95</b> are molded into the coupler <b>34</b> to assist in preventing turbulence and directing air from the pin <b>92</b> to the overflow chambers <b>94</b> and <b>96</b>.

The overflow chambers <b>94</b> and <b>96</b> are designed such that the resulting overflow members <b>97</b> and <b>98</b> may be removed, via manual or automatic trimming (step <b>110</b>), from the final part configuration. The remnants of the overflow members <b>97</b> and <b>98</b> will be part of the molded features that define the interfaces with the control valves <b>30</b> and <b>32</b>. The part remaining after the trimming operation is the waterway or coupler <b>34</b> providing fluid communication from both control valves <b>30</b> and <b>32</b> to the outlet tube <b>38</b>.

In certain illustrative embodiments, the polyethylene of the tubes <b>20</b> and <b>22</b> and coupler <b>34</b> are then cross-linked to form cross-linked polyethylene (PEX) at step <b>112</b>. In other words, the polyethylene of tubes <b>20</b> and <b>22</b> and coupler <b>34</b> (which have not been cross-linked or have been only partially cross-linked) are cross-linked following the overmolding process. While it is envisioned that any form of suitable cross-linking may be utilized to form the PEX of tubes <b>20</b> and <b>22</b> and coupler <b>34</b>, in one illustrative embodiment the polyethylene is cross-linked by bombarding it with electromagnetic (gamma) or high energy electron (beta) radiation. In the illustrative embodiment, no subsequent machining operations are required on surfaces of the valve interfaces <b>52</b> and <b>56</b> and the outlet tube interface <b>58</b> to sealingly engage with gaskets <b>70</b> and o-ring <b>74</b>, respectively.

While the precise composition of the tubes <b>20</b> and <b>22</b> and overmolded coupler <b>34</b> are not required to be of any specified polymer, in general, there are several guidelines which are applicable in the practice of the illustrative embodiment. It is of course, recognized that the precise operating conditions utilized in the overmolding process are well-known in the art and are specific to each molded polymer. It is well within the skill of the art to determine the applicable conditions which will result in the appropriate overmolded coupler <b>34</b> and tubes <b>20</b> and <b>22</b>. The tubes <b>20</b> and <b>22</b> and coupler <b>34</b> may be a thermoplastic or a thermoset. Illustratively, the polymer overmolded coupler <b>34</b> should be capable of forming a leak-proof bond, either chemical or physical, with the polymer of the tubes <b>20</b> and <b>22</b>.

Illustrative and non-limiting examples of the polymers which may be used in various combinations to form the tubes <b>20</b> and <b>22</b> as well as polymers which may be used in the overmolding process would include: polyacetals, typically highly crystalline linear thermoplastic polymers of oxymethylene units; poly(meth)acrylics, typically belonging to two families of esters, acrylates and methacrylates; polyarylether ketones containing ether and ketone groups combined with phenyl rings in different sequences and polyether ketones; polyacrylonitrile resins wherein the principal monomer is acrylonitrile; nylons or polyamides, including various types of nylon-6, nylon-6/6, nylon-6/9, nylon-6/10, nylon-6/12, nylon-11, nylon-12; polyamide-imides formed by the condensation of trimellitic anhydride and various aromatic diamines; polyacrylates of aromatic polyesters derived from aromatic dicarboxylic acids and diphenols; polybutene resins based on poly(1-butene); polycarbonates, typically based on bisphenol A reacted with carbonyl chloride; polyalkylene terephthalates typically formed in a transesterification reaction between a diol and dimethyl terephthalate; polyetherimides, based on repeating aromatic imide and ether units; polyethylene homopolymers and copolymers, including all molecular weight and density ranges and degrees of crosslinking; polypropylene homopolymers and copolymers; ethylene acid copolymers from the copolymerization of ethylene with acrylic or methacrylic acid or their corresponding acrylate resins; ethylene-vinyl acetate copolymers from the copolymerization of ethylene and vinyl acetate; ethylene-vinyl alcohol copolymers; polyimides derived from the aromatic diamines and aromatic dianhydrides; polyphenylene oxides including polystyrene miscible blends; polyphenylene sulfides; acrylonitrile butadiene styrene terpolymers; polystyrenes; styrene-acrylonitrile copolymers; styrene-butadiene copolymers thermoplastic block copolymers; styrene maleic anhydride copolymers; polyarylsulfones; polyethersulfones; polysulfones; thermoplastic elastomers covering a hardness range of from 30 Shore A to 75 Shore D, including styrenic block copolymers, polyolefin blends (TPOS), elastomeric alloys, thermoplastic polyurethanes (TPUS), thermoplastic copolyesters, and thermoplastic polyamides; polyvinyl chlorides and chlorinated polyvinyl chlorides; polyvinylidene chlorides; allyl thermosets of allyl esters based on monobasic and dibasic acids; bismaleimides based generally on the condensation reaction of a diamine with maleic anhydride; epoxy resins containing the epoxy or oxirane group, including those epoxy resins based on bisphenol A and epichlorohydrin as well as those based on the epoxidation of multifunctional structures derived from phenols and formaldehyde or aromatic amines and aminophenols; phenolic resins; unsaturated thermoset polyesters including those of the condensation product of an unsaturated dibasic acid (typically maleic anhydride) and a glycol, wherein the degree of unsaturation is varied by including a saturated dibasic acid; thermoset polyimides; polyurethanes containing a plurality of carbamate linkages; and urea and melamine formaldehyde resins (typically formed by the controlled reaction of formaldehyde with various compounds that contain the amino group).

The combination of the above polymers illustratively satisfy at least two simultaneous conditions. First, the tubes <b>20</b> and <b>22</b> illustratively do not soften and begin melt flow to the point where they lose structural integrity and second, the overmolded coupler <b>34</b> is illustratively capable of forming an essentially leak-proof interface with the plastic conduit, preferably through either a chemical and/or physical bond between the underlying plastic and the overmolded plastic. According to the illustrative embodiment, the tubes <b>20</b> and <b>22</b> are capable of maintaining structural integrity during the overmolding conditions during which the overmolded polymer is in melt flow.

While using polymer compositions which have differing softening points is one way to achieve the above objectives, there are alternatives, one of which would include the use of two compositions which have the same softening point, but which are of different thickness. Through manipulation of the time, temperature and pressure conditions experienced during the molding operation, the tubes <b>20</b>, <b>22</b> would not experience melt flow, even though they had a similar softening point or range. It is also possible that through the incorporation of various additives in the polymeric compositions, e.g., glass fibers, heat stabilizers, anti-oxidants, plasticizers, etc., the softening temperatures of the polymers may be controlled.

In an illustrative embodiment of the invention, the composition of the overmolded coupler <b>34</b> will be such that it will be capable of at least some melt fusion with the composition of the tubes <b>20</b> and <b>22</b>, thereby maximizing the leak-proof characteristics of the interface between the tubes <b>20</b> and <b>22</b> and overmolded coupler <b>34</b>. There are several means by which this may be effected. One of the simplest procedures is to insure that at least a component of each tube <b>20</b>, <b>22</b> and that of the overmold coupler <b>34</b> is the same. Alternatively, it would be possible to insure that at least a portion of the polymer composition of each tube <b>20</b>, <b>22</b> and that of the overmold coupler <b>34</b> is sufficiently similar or compatible so as to permit the melt fusion or blending or alloying to occur at least in the interfacial region between the exterior of the tube <b>20</b>, <b>22</b> and the interior region of the overmold coupler <b>34</b>. Another manner in which to state this would be to indicate that at least a portion of the polymer compositions of the tube <b>20</b>, <b>22</b> and the overmold coupler <b>34</b> are miscible.

In yet another illustrative embodiment, composites of rubber/thermoplastic blends are useful in adhering to thermoplastic materials used in the tubes <b>20</b> and <b>22</b>. These blends are typically in the form of a thermoplastic matrix containing rubber nodules functionalized and vulcanized during the mixing with the thermoplastic. The composite article is then obtained by overmolding the vulcanized rubber/thermoplastic blend onto the thermoplastic conduit. In this manner, the cohesion at the interface between these two materials is generally higher than the tensile strength of each of the two materials.

Although the invention has been described in detail with reference to certain preferred embodiments, variations and modifications exist within the spirit and scope of the invention as described and defined in the following claims.